Plaster ground



Oct. 7, 1958 H. H. LAMB 2,854,843

PLASTER. GROUND Filed Dec. 15, 1955 2 Sheets-Sheet 1 n [HF a a a/ 1r 1. 12 INVENTOR.

HERBERT H. LAMB ATTORNEY United States Patent fihce LASTER GROUND Herbert H. Lamb, Warren, Ohio Application December 13, 1955, Serial No. 552,821

1 Claim. (Cl. 72-128) The present invention relates to a device for outlining a wall opening to provide an abutment for guiding the application of plaster to the wall portion adjacent such opening, and the principal object of the invention is to provide new and improved devices of such character.

Devices of the above described character have long been used in the building trades and are commonly known as plaster grounds. These devices, as presently used, comprise wooden strips secured to the framing which defines the wall opening, the strips being of sufficient thickness to protrude from the wall an amount equal to the desired thickness of the plaster to be applied. After the plaster hardens, the usual trim is applied.

To reduce costs, the strips usually employed are not first grade lumber and many times a plurality of pieces are placed in end to end abutting relation to form a strip of suflicient length. Since the strips are relatively rough and are sometimes formed of pieces in end to end abutting relation, the guide surface provided by the pieces is somewhat rough. This is particularly true if the pieces employed are not of identical thickness. Furthermore, the strips sometimes warp as a result of their contact with the wet plaster and, accordingly, such strips must at times be replaced before the trim is applied in order to insure that the trim fits properly.

The present invention provides plaster grounds which possess none of the disadvantages of prior art plaster grounds. Other advantages will readily become apparent from a study of the following description and from the drawings appended hereto.

In the drawings accompanying this specification and forming a part of this application, there is shown, for purpose of illustration, an embodiment which the invention may assume; and, in these drawings:

Figure 1 is a perspective view of a preferred embodiment of the invention,

Figure 2 is an enlarged, fragmentary, exploded perspective view of the embodiment shown in Figure 1,

Figure 3 is an enlarged transverse sectional view generally corresponding to the line 3-3 of Figure 1 and showing the invention positioned for use within a wall opening,

Figure 4 is a fragmentary perspective view of a conventional building wall prior to the application of plaster thereto, and

Figures 5 and 6 are enlarged sectional views generally corresponding to respective lines 5-5 and 6-6 of Figure 4.

In the presently disclosed embodiment, the invention is adapted for use with wall openings which extend to the floor and in which a door or the like is subsequently adapted to be positioned. It is to be understood, however, that the invention may also be used With wall openings which do not extend to the floor and in which windows or the like are subsequently adapted to be positioned.

Referring to Figure 1, the embodiment therein dis- Fatented Oct. '2, 1958 closed comprises a frame formed of a pair of spaced, parallel side legs 10 connected at their upper ends (in the position of parts shown) by a transverse leg 11. For a purpose to be shown, each leg is adjustable in length.

At the present time, it is preferred to form the legs of relatively thin sheet metal to provide a channel-like cross section having opposed sides turned inwardly toward each other (see Figures 2 and 3). Each leg 10 is formed of a pair of members 12 joined together by a member 13. Member 13 has the same cross section as do members 12; however, member 13 is proportioned to slidably fit within members 12 as will be clear. If desired, member 13 may be held to sliding movement with only one of the members 12 by welding or otherwise securing member 13 to the other member 12 in axially extending relation, as shown.

Slidably carried by the upper end of each upper member 12 is a member 14 which is similar to member 13. Each member 14 slidably fits within the vertical leg of respective angle, or corner, members 15. The horizontal legs of the angle members 15 are adapted to he slidably connected by means of a member 16 which fits within the horizontal legs of the angle members and which is similar to members 13, 14 except for its longer length. For a purpose to appear, legs 10, 11 are apertured, as indicated at a, to permit the legs to be nailed or otherwise temporarily secured within a wall aperture.

Figure 4 illustrates a conventional wall construction prior to the time the plaster is applied. This wall is formed by the usual upright studding members 17 to which are secured the usual lath members 18. For simplicity, the lath members are shown spaced further apart than would actually be the case. The wall herein illustrated is provided with a door opening, the studding members 17a which define such opening being reinforced by similar members 17b placed in side-by-side relation therewith. Extending across between the studs defining the opening is a header member 19 which defines the top of the wall opening.

As illustrated in Figures 5 and 6, the conventional plas ter ground comprises wooden strips S secured to opposite sides of the header 19 and similar strips secured to opposite sides of respective studs 17a. These strips are of a thickness to project from the wall beyond the lath members an amount equal to the desired thickness of the plaster to be applied.

The present invention is adapted to replace the conventional plaster ground with its attendant disadvantages. The frame is adapted to be positioned within the wall opening with leg 11 abutting header member 19 and with legs 10 abutting respective studding members 17a. It will be understood that the legs will first be shortened to permit the frame to be positioned within the opening and then lengthened to insure that each leg lies closely against the respective wall members defining the opening. The frame may then be temporarily secured in position by nails or the like which pass through apertures in the legs and into the members defining the wall opening.

As shown in Figure 3 wherein the frame is positioned within the wall opening, leg 10 of the frame is of such width that it projects beyond lath members 18 an amount equal to the desired thickness of the plaster to be applied.

Upon securement of the frame in position, the wall may then be covered with plaster 20, it being apparent that portions 21 of the legs provide smooth, well-defined, abutments against which the plaster is applied and portions 22 of the legs provide smooth edges which guide a Workman in applying the proper thickness of plaster.

After the plaster has set, the nails securing the frame will be pulled and the legs then shortened to permit easy removal of the frame without damaging the sur-v 3 rounding plaster edges. The wall opening may then be trimmed or otherwise completed in the usual manner.

In view of the foregoing it will be apparent to those skilled in the art that I have accomplished at least the principal object of my invention and it will also be apparent to those skilled in the art that the embodiment herein described may be variously changed and modified,

without departing from the spirit of the invention, and

that the invention is capable of uses and has advantages not herein specifically described, hence it will be appreciated that the herein disclosed embodiments are illustrative only, and that my invention is not limited thereto.

I claim:

For use in plastering around a wall opening such as defined by spaced parallel vertical studs connected by a horizontal header, the vertical studs having a plurality of lath members secured flatwise to side surfaces thereof and extending in the plane of the wall away from the wall opening, the improvement comprising a plaster ground providing a temporary frame within the rectangular confines of said wall opening and used to guide trowelling of plaster around said opening, said plaster ground having spaced vertical legs and a horizontal leg corresponding to the aforesaid studs and header, each of said vertical legs comprising a pair of sheet-metal channel sections telescopically and closely but slidably fitting together and said horizontal leg also being formed of sheet-metal channel of a transverse size and configuration substantially identical to that of said vertical legs, and a pair of upper corner members each of sheet-metal channel section and each bent to right angle formation to provide a horizontal portion telescopically and closely but slidably fitting a respective end of said horizontal leg and a vertical portion telescopically and closely but slidably fitting the upper end of a respective vertical leg, whereby a metal frame is provided of substantially uniform width throughout its extent, the width of said frame being greater than the thickness of the wall at said opening, said frame being adjustable vertically and horizontally to fit within the confines of wall openings of various sizes and being temporarily secured within a wall opening with the webs of the channels of the vertical and horizontal legs and the corner members applied against corresponding inside surfaces of said studs and header and with said webs extending beyond the adjoining side marginal portion of said wall opening, the legs of the channels of the vertical and horizontal legs and corner members extending inwardly of the frame and providing a smooth guide surface margining the side of said wall opening for guiding trowelling movements in the application of plaster covering said laths and surrounding said wall opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,697,300 Baum Jan. 1, 1929 1,791,822 Lundquist Feb. 10, 1931 2,502,166 McKay Mar. 28, 1950 2,616,145 Dufiord Nov. 4, 1952 2,725,608 Parslow Dec. 6, 1955 FOREIGN PATENTS 550,078 Great Britain Dec. 22, 1942 

